FIGURE 7.

Principal component analysis of electrophysiological properties of neurons during early development. (A) Polar plot showing the respective contribution of each of the 15 electrophysiological parameters to the two principal components retained from the PCA (PC1 and PC2). (B) Scatter plot representing the factor loadings of the 132 neurons and the averaged factor loadings for each age and each methadone treatment of cortical organoids. Error bars represent the standard error of the mean. This PCA integrates intrinsic electrophysiological properties including passive membrane properties, APs frequency and properties, current sizes and gating properties of Na⁺ and K⁺ channels. Glia or other non-functional cells were not included in the PCA. Neurons that did not have unambiguous analysis of all the chosen 15 electrophysiological properties were also excluded from this PCA analysis.